Endocrine System Flashcards
Endocrine gland
Glands which secrete hormones into extracellular fluid that surrounds the cells that make up the gland. The secretion then usually passes into the capillaries to be transported by the blood.
Hormones
Hormones are a chemical secreted by specialised cells to be transported in the blood stream. They are slow to be produced, the action is long lasting and wide spread. Hormones are only able to cause an effect on cells that have the correct receptor for the hormone, receptors are specific. Once all receptor molecules are occupied by hormone molecules, any addition of hormones will not have an effect.
Steroid hormone
Steroid hormones are lipid soluble and carried in blood stream by a protein carrier. These hormones have the ability to pass through the membrane.
Steroid hormones process
- Passes through the membrane.
- Locks onto a protein in the cytoplasm or nucleus forming a hormone-receptor complex.
- Hormone-receptor complex attaches to the DNA and regulates transcription (alters gene expression). The effects of these hormones are exerted more slowly and can take days..
Amine/protein hormones
Amine hormones are water soluble, they dissolve in the blood (bloods main component is water) therefore transported in the blood stream. The hormones cannot pass through the membrane.
Amine/protein hormone process
- Locks onto a specific receptor in the membrane.
- Causes the production of a secondary messenger in the cytoplasm.
- Secondary messenger will then cause a response inside the cell. Immediate effects. Eg. affect enzyme functioning.
Posterior pituitary stores which hormones?
ADH
OXYTOCIN
Anterior pituitary produces
FLAT PG
ACTH GROWTH HORMONE FSH THYROID STIMULATING LUTEINISING HORMONE PROLACTIN
Pineal gland produces
melatonin
Thyroid produces
thryoxine
calcitonin
Parathyroid produces
parathyroid hormone
Thymus produces
thymosin
Adrenal cortex produces
cortisol
aldosterone
Adrenal medulla produces
adrenaline/epinephrine
noradrenaline/norepinephrine
Pancreas produces
insulin
glucagon
Testes produces
testosterone/androgens
Ovaries produces
oestrogen
progesterone
ADH (antidiuretic)
target cell- kidney
effect- Increases the permeability of the distal convoluted tubule, enabling more water to be absorbed, increasing water levels
Oxytocin
target cell- uterus and mammary glands.
effect- Triggers contractions and milk let down reflex
ACTH (adrenocorticotropic)
target cell- adrenal cortex
effect- Causes the release of corticostecoids (cortisol)
Growth hormone
target cells - body cells
effect- causes growth
FSH
target cells- ovaries and testes
effect- stimulates follicle growth and triggers spermatogenesis.
Thyroid stimulating hormone
target cells- thyroid gland
effect- stimulates thyroid to produces thyroxine
Luteinising hormone
target cells- ovaries and testes.
effect- Causes ovulation.
Causes production of testosterone.
Prolactin
target cell- mammary glands
effect- produces breast milk
Melatonin
target cells- brain
effect- Sleep. Stimulated by darkness and inhibited by light. Gland shrinks during puberty.
Thyroxine
target cells- body cells
effect- increases metabolism
Calcitonin
target cells- bones
effect-removes calcium from blood into bones
Parathyroid hormone
target cells- blood cells and digestive systems.
effect- Removes calcium in from bones, into the blood.
Increases the absorption of calcium from the digestive system.
Thymosin
target cells- thymus
effect- maturation of T-cells
Cortisol
target cells -body cells
effect- Stress hormone. Helps the body repair when under stress and mobilises resources of glucose.
Aldosterone
target cells-kidney (nephron)
effect- Water control. Increases the absorption of sodium from the nephron and increases the removal of potassium (amount of potassium in nephron increases).
Adrenaline
target cells- body cells
effect- fight or flight response
Noradrenaline
target cells- body cells
effect- fight or flight response
Insulin
target cell- liver and body
effect-takes sugar out of blood.
Glucagon
target cell- liver and body cell
effect - puts sugar in blood.
Testosterone
target cell - body cells
effect- secondary sexual characteristics
Oestrogen
target cell - body cells
effect- secondary sexual characteristics
Progesterone
target cells - uterus
effect - effects lining of the uterus.
The pituitary gland
An extension of the hypothalamus, it is a pea sized gland located at the bottom of the brain. It is divided into two, the anterior and posterior pituitary which are both responsible for the secretion of hormones that control other gland and many bodily functions
Anterior pituitary gland
The anterior (front) lobe has no nerves connecting it to the hypothalamus, instead it has a large network of blood vessels. The anterior produces hormones.
Posterior pituitary
The posterior lobe, is not considered a true endocrine gland as it does not produce its own hormones. The posterior receives hormones made by the hypothalamus, it is joined to the hypothalamus by nerve fibres that come from nerve cell bodies in hypothalamus and pass through infundibulum to posterior lobe.
Process by which hypothalamus controls Release of hormones
- ADH and oxytocin are made in the hypothalamus and sent down nerve cell extensions to be stored in posterior.
- Hypothalamus sends nerve impulse down extensions to cause the release of hormones from posterior pituitary into blood stream/vessels.
- Hypothalamus also makes releasing or inhibiting factors into the blood stream.
- Factors diffuse into anterior pituitary and tell it to release/stop releasing hormones. If released hormones diffuse from AP into the blood stream.
What is hyperthyroidism, who does it effect
Hyperthyroidism is caused by the overstimulation of the thyroid gland. People suffering from Grave’s disease which is an abnormality of the immune system, may also have hyperthyroidism. This is because Grave’s disease creates antibodies which behave like TSH and stimulate the thyroid uncontrollably. Hyperthyroidism also effects people who produce excessive amounts of TSH or too much iodine.
Symptoms of hyperthyroidism
Rapid heartbeat, weight loss, increased appetite, fatigue, increased metabolism, fatigue, don’t like heat as they cannot cool themselves down.
Treatments of hyperthyroidism
Drugs that block the thyroids use of iodine, surgery to remove part of the gland. Can consume radioactive iodine, the iodine molecules are taken up by the thyroid cells which are then killed by the radioactivity. The thyroid gland is the only gland to take in iodine, therefore the treatment is safe. The risks of these treatments is giving the person hypothyroidism.
What is hypothyroidism and who does it effect
Hyperthyroidism is caused by low activity in the thyroid gland. Women are more commonly affected by this disease, and those with Hashimoto’s disease are affected. Possible causes of the condition are low levels of iodine in the diet which prevents the ability of the gland to make sufficient hormones.
Symptoms of hypothyroidism
Certain body functions slow down which leads to fatigue, slow heart rate, unexplainable weight gain, intolerance to cold, swelling of the face and goitre (goitre caused by the gland enlarging in an effort to produce more).
Detection of cause of hypothyroidism
Give the subject iodine and observe if the problem resolves (low iodine in diet would be cause). Blood test measure TSH levels, if injected with TSH and no change, clearly the thyroid at fault, if thyroxin levels do no change the pituitary is at fault.
Treatments of hypothyroidism
Intake of synthetic hormone TSH or thyroxine (made through recombinant DNA process) and balanced diet (iodine levels focus). Risk of these treatments is giving the patient hyperthyroidism.
What is type one diabetes
Type one diabetes is a genetic disease, a lifelong condition (juvenile), it is not caused by lifestyle. Diabetes is caused by the immune system attacking beta cells in the pancreas, this leads to no or minimal insulin being available in the body, thus blood sugar builds up. The exact cause of the condition is unknown, the immune system attacks and destroys insulin-producing cells in the pancreas, which leaves little or no insulin therefore sugar builds up in your bloodstream, instead of being transported into your cells. Occurs in the genes and inheritance.
Symptoms of type one and two diabetes
Increased thirst, frequent urination (caused by sugar in blood, water passes from cells into blood = high blood pressure, more urination and dehydration), extreme hunger; even after eating, fatigue & weakness, unintended weight loss or weight gain, nausea, skin infections.
Detection of type one and two diabetes
Sugar in the urine is first indicator, glycated haemoglobin test (blood test indicates your average blood sugar level for the past two to three months), fasting blood sugar test or a blood sample is taken after an overnight fast.
Treatments of type one diabetes
Insulin replacement, insulin injections (up to 6 a day), insulin pump- monitors blood glucose levels, stem cell replacement, mmanufacturing pancreas islet cells (beta cells) from stem cells (ttemporary relief before the immune system breaks down the cells benefits is their own cells so no chance of rejection), ppancreas transplants (high chance of rejection, needs to be obtained ethically).
What is type two diabetes
Type two diabetes is a self-inflicted condition in which fat, liver and muscle cells can no longer respond to insulin (adult on set). It is caused by an unhealthy lifestyle, which results in muscle, fat and liver cells are overstimulated by insulin, creating a resistance. Being overweight, lacking in exercise and eating unhealthy food increases the risk of type 2 diabetes.
Treatment of type two diabetes.
A change of diet including a management program to keep blood glucose levels in the normal range.
Medication (if management program doesn’t make your blood glucose levels controlled), drug increases the sensibility to body tissues and makes your body use insulin more effectively.
Regular physical activity and maintaining a healthy weight can also reduce effects of type two diabetes.
Type two can be reversed if detected early enough and lifestyle choices are corrected.
Process of making synthetic hormones (Recombinant DNA)
- Human DNA containing the gene for desired hormone is obtained. The desired gene is cut out at the restriction site using restriction enzymes. This gives a base sequence to which the hormone would be produced.
- A bacterium containing chromosomal DNA and a ring of DNA that acted as the bacteria’s defence system known as plasmid is obtained. The plasmid is extracted
- The restriction Enzyme is used to cut the plasmid (same enzyme used in cutting desired gene).
- The human gene is then combined with the plasmid to create recombined DNA. DNA ligase (enzyme) glues the DNA into place, this process is called ligation.
- The recombinant DNA is then placed back into the bacteria. The bacteria breed in a fermenter (the perfect environment for bacteria to breed). Thousands of the hormone produced.
- The bacteria make hormone which is collected cells then purified and ready to be used.
